When I was a youngster my parents bought me a pair of braces to hold up my new trousers. Of course these were 'Trousers to grow into' and without such support I would have been running around bare arsed. The braces were blue and had pictures of planets and rockets and, in the box, was a genuine ticket to the Moon.
I know, because it said so.
Somewhere in a landfill site, many many years ago...

Saturday, 31 May 2008

Heimdall crater, Mars. Just south of the northern polar ice cap, but inside the 'arctic circle'.

OK it don't look like much, just another crater, yawn... Read on for the background before I show the full image. (grin)Late last Sunday Night/Monday morning (25th/26th May) I had the best white knuckle ride for years. The Phoenix lander made safe touchdown on Mars. I was sat at home, watching NASA TV on the net with live video and commentary from the control room, and the atmosphere was electric. For the last few minutes I was hanging onto my desk and willing this thing down. (of course the radio signal takes time to come to Earth, about 15 mins that night, so it all had happened by the time anyone knew).

But, touchdown! It all worked, and by 'all' I mean watch this simulation...

OK it's a CGI simulation, but it may give a feel of the occasion. Note also that this thing comes down on thrusters. That's technically very difficult. Usually parachutes are used slow the craft enough for airbags to absorb the shock of impact. Phoenix was too heavy for this, it's carrying a lot of science hardware. Phoenix flew!

Satellite ballet

At the same time, the flight controllers of three (count them) satellites currently in orbit around Mars had re-positioned their crafts to relay data, take photos, and provide backup. Phoenix is coming in from the top left

NASA'sMars Reconnaissance Orbiter (MRO) is on point to relay signals and take pictures with the best camera ever. Nearby is Mars Odyssey, and Europe's Mars Express in a wider orbit but close enough to (metaphorically) give them a wave and pick up the baton should there be major problems.

However it all went to the perfection of ballet, or better. Signals from the lander were coming in, high fives were given round the control room and I'm sure only just missed the champagne as I went to bed.

First ImagesMonday morning I woke up to pictures like these:

First view of Mars

Phoenix checks out one if it's 3 landing legs.

Where did it land?Here's a rough idea of the landing siteThe blue ellipse is the area of the predicted landing zone. That's where Phoenix was aiming. The red circle encloses where It really did land, the red dot is the most probable place. It seems Phoenix almost overran the target. Something happened.

I've heard that the parachute deployed a bit late, I've also heard that it should have opened as Phoenix reached a certain speed. Did mission control underestimate local air pressure? They got the weather wrong maybe? Well that's not surprising.

The thing to note is the big round orange blob just right of Phoenix. That is Heimdall crater from the first image above. The red rectangle is/was the predicted path of MRO with the amazing HiRISE camera aboard. As Phoenix comes down and MRO goes overhead, HiRISE is aimed, guided by radio triangulation with Odyssey i guess, so it's pointing to the East and down a bit towards Heimdall crater, and HiRISE took a picture.

This is the first OMG shot I sawHere's a blowupIt's amazing. A man made object descending onto an alien world, photographed by another man made object. Phil Plait, the Bad Astronomer, says it much better than I can.

But all of this is just a teaser for the real image.Click on the picture to see it full screen - get it as big as you can. Then sit back in awe as to what humans can do.

Note: Heimdall crater is 10km across and Phoenix is much closer to the camera than it appears, about 20km closer.